The first goal of this project is to assess the feasibility of using a newly developed, rapid, high resolution, visual mapping procedure for the mapping of yeast artificial chromosomes. The assembly of maps from yeast artificial chromosomes for the human genome will facilitate identification of genetic disorders and the gene responsible. The second goal is to improve this new mapping procedure by developing a multi-color multi-probe strategy and developing computer software capable of analyzing the visual images that are generated. These improvements will allow faster mapping as well as provide the ability to rapidly and precisely detect gene rearrangements involved in human disorders. The new mapping technology that will be used involves the stretching of human genomic DNA on a slide and hybridizing fluorescent DNA probes to the extended DNA strands. The result is a multi-color string as viewed through a fluorescence microscope and represent a map of the DNA region of interest. Resolution as low as .4 Kb has been obtained. Yeast artificial chromosomes from human chromosome 3 will be studied with this technology.